ISOMORPHISM INVARIANTS FOR ABELIAN-GROUPS

Let A = (A1,...,A(n)) be an n-tuple of subgroups of the additive group, Q, of rational numbers and let G(A) be the kernel of the summation map A1 + ... + A(n) --> SIGMA-A(i) and G[A] the cokernel of the diagonal embedding union A(i) --> A1 + ... + A(n). A complete set of isomorphism invariants for all strongly indecomposable abelian groups of the form G(A), respectively, G[A], is given. These invariants are then extended to complete sets of isomorphism invariants for direct sums of such groups and for a class of mixed abelian groups properly containing the class of Warfield groups.